The Grunka Lunkas are small orange men who inhabit the planet Wormulon. They are employed by the Slurm Worms to work in the fake Slurm Factory. They spontaneously burst into song with a warning about asking questions of Glurmo. They aren't paid to sing and Glurmo denies them their bathroom break for singing when they should be working.

They try to sing again later but are repeatedly silenced by Bender and Glurmo.